Project 49

[noday]

do you think the vibration is killing the leds ? that was mentioned before

then to shift gears, did you change the front brake ?

I saw you remove the "ABS"

do you put on a larger front rotor for more braking at increased speed ?

thanks

[90GTVert]

Prob is vibration. Whenever I've removed any tail light there is always dust in there from the circuit board or lens or whatever. I ordered a truck/trailer light that mounts in a grommet. Not sure how easy it'll be to make it work, but maybe that'll kill some of the vibrations if I get it working. I was already using rubber washers, but that didn't do it I guess. The truck trailer light setup would also offer easy to find replacement lights, should be bright, and I dunno what would be much tougher.

I have no ABS, but stock brakes. Both of my Tritons stop OK from 70MPH. Doubt the 70cc is gonna be anywhere near that. I could use more brake power, but they aren't bad. Maybe I just feel that way cause I owned a SunL with horrible drums and I struggled to stop from 25 at times with it? Some seem to hate their brakes, but I'm way heavier than the avg rider and don't really complain. Weight may be good on the front? I know I've seen smaller friends lock up the front brakes. I cannot make that happen.

[noday]

I remember the SunL escapade well, it brought me to 49ccScoot

you answered my questions

thanks

[90GTVert]

I've been messing around more this morning, and it's in tune now. I tried a 75 main jet and a new spark plug. Ran fine, CHT got up to 330 where I expected it. Checked the plug and it wasn't putting enough color into the mixture ring. Back to an 80 and it looked good, CHT closter to 300. It's not super hot right now, as it has been all summer, so that may play a role, but I assume CHT probe placement is doing a big part and the fin layout. This head has a lot of fins and it also puts the probe up higher where it would get more airflow. Other than CHT and doing the mixture/smoke ring reads, I really couldn't tell much difference between 75, 80, and 85 mains. I believe a little less performance at 85, but it was close. Ended up using the same jet as the stock cylinder.

I then moved to the CVT. It was running well to begin with, but I wanted to see if there was more to be had. After fooling around for a while, I ended up with 4.5g sliders, but with the spacer removed from the stock variator setup. I couldn't tell much difference with or without the spacer at launch with the big bore. Cruising it did pretty much nothing for MPH with or without the spacer. The big reasons I left it out were that I could get the same cruise speed at a lower RPM and I assume that should I catch a tail wind or tuck down I may be able to get more out of it without the spacer.

Tuning with the 68cc has been simple. I think I could have probably used from 75-85 main jets and if not paying much attention to plug reads and CHT, there wouldn't be a big difference. I could tune the trans with or without the spacer in place and with anywhere from 4.5 - 6g sliders and get pretty good results. The pipes, even with the stock cylinder porting that didn't show big gains, were not nearly that forgiving on tune. To get acceleration and speeds that compare to what I'm seeing now, I had to go to the aftermarket variator, rework the stock drive face, get spacers just right, and make sure the clutch springs were working to their absolute best ability. It's definitely easier to bolt the pipe on, but I wanted to pull my hair out while trying to get the tune just right. Personally, I'd rather do more mechanical work installing the big bore and then have an engine that pulls harder over a greater RPM range and cruises at a more steady speed. I can't honestly see how anyone could ride the two and say the 49cc is better. Maybe it's because I'm fat, but the additional torque is a huge asset.

Here's one way I can tell a torque difference without even getting on the scooter. With the 49cc cylinder the idle would drop considerably when I turned on the lights. Now it hardly changes. Pretty sad when the lighting circuit is that much of a burden to the engine.

[oldgeek]

So it sounds like a 70bbk is much less hassle than trying to squeeze everything you can out of the 50cc...that is good to know, THANKS for all the work and data you provide.

Can you tell me what kind if any markings the Autotech355 bbk has on them? I want to keep it LOOKING stock if possible. I have a feeling that scooter laws are going to see some changes by next year around here, and 68cc on the block will not help.

[90GTVert]

I'm way happier riding the big bored scoot than the piped scoot. I've got more results, but I've been staring at the screen for a long while now putting together a video and I've had enough ATM. I'll get that up tomorrow hopefully.

It doesn't say anywhere what cc. It has some seemingly random numbers on one side and a name that starts with an S on the other. Sorry, I forget right now. Nothing that would tell the avg person it's a big bore by name or number.

[90GTVert]

After using the stock variator, I switched to the Hoca variator, 2mm of spacers, modified fixed half, and 6.5g sliders. I miss riding farther than my test strip, so I took a 53 mile ride last night. Cruise speeds were very consistent at 43-45MPH. The lowest I saw was 41MPH up a mild incline into prob a 5MPH headwind. Highest speed was 49MPH, sitting up, on a decline. There are some flags right by where I hit max speed, and they weren't moving from wind at the time. The big bore kit should have 50MPH in it pretty easily if you wanted to tuck down, or maybe just with a lighter rider. When the slight wind was in my favor I was seeing 46-48MPH on flat ground sitting up.




I did 0-35MPH runs with both setups. The stock variator put performance even with the fastest of the ported cylinder and pipe setups that had to use the Hoca variator with the modded drive face and heavy tuning to keep within peak RPM. Much faster than anything the pipes would have done with no cylinder mods. The Hoca knocked another 1/2 second off of the 0-35MPH time, for the fastest I've seen so far.




An added benefit of the all around power the big bore gives is that RPM stays lower. Instead of turning 9,000+ with the pipes, I was cruising in the low to mid 8,000RPM range.


Since I have given hardly any gas mileage numbers from the lack of long rides, I checked mileage last night. The plan was to cruise around 40MPH like I did with near stock setups and see how the 68cc compared. The plan failed. I was enjoying riding and rode WOT pretty much everywhere. Even in towns I was going way too fast. Sorry, like I said earlier, I missed taking a ride instead of just test runs. Even with me riding like a fool, fuel economy was 47.9MPG. That's roughly 10MPG less than the best I saw when the engine was stock, but I'm pretty sure I could see within 5MPG if I were to cruise at the speeds the stock scooter could do and did not ride aggressively in towns and such. I never checked MPG on the piped and ported setups at a pump, but I filled the tank and ran out of gas in 47 miles once. Another time I looked in the tank at 40 miles from filling and there was barely anything left. If you take the 47 miles on a 1.4 gallon tank, that's only 33.6MPG. I'm not sure that's totally accurate, but it at least tells me the big bore kit should be getting better mileage than the ported and piped stock bore. I should note the poor economy was with the MRP in both cases, needing to stay at high rev at all times.


While I'm very pleased with the big bore kit, I do want to not that I've seen others report their kits not wanting to work with a stock pipe. I would suggest sticking with a cast iron sport kit unless a pipe is coming with it. Even with a pipe, I prefer the more mild iron kits for the street. You have the ability to port them if you want or need to with relative ease, and in stock form most shouldn't be so wild that they won't work with a stock pipe (providing it has no restrictions, and again of course not all pipes are made the same). You don't run as big of a risk of putting a hole in the piston, because you're more likely to get a soft seize with an iron bore and aluminum piston. Not that a soft seize is a good thing, but you'll be a lot more likely to ride away from a soft seize.

[90GTVert]

More power! For free!!!




I tried to get a quick ride in this morning to see what top speed may be now. Weather is wet again and CHT was running low. It still ran OK, but not like it was last night without all the wet air. 52MPH max, but that was on a short little hill and tucked. Still, it feels good with the added compression. Gains aren't huge, but you can definitely feel a little more grunt.

[90GTVert]

First, a quick note. I finally checked cranking compression to see the difference without the head gasket. It started at 155psi and went to 177psi.


I installed the Leo Vince SP3 exhaust. Went from an 80 main jet to a 90. Changed from 6.5g sliders to 6g. I didn't seem to gain any revs. The main difference was that it felt like more torque than before. Tucked down on a flat stretch with no wind I saw 50MPH. I could do that with the stock exhaust. I really hoped to see a lot more out of it. I think the low end power would do much more if I were still using a stock variator so the operating RPM range was wider. Check it out...

[noday]

what am I missing ? is the sp3 peaky like the ZX ?

www.pedparts.co.uk/blog/chinese-2-stroke-moped-tuning-baotian-falcon

that power decline after the peak seems to say, no usable power for more speed ?

[90GTVert]

Power past peak isn't as important when not using the stock variator. The Hoca really doesn't have a big tendency to push past where it's tuned to be other than maybe tucked down or strong tailwinds or hills. The stock variator was seeing 9000RPM with the stock exhaust. Once in tune I was in the low 8000RPM range most of the time WOT with the Hoca. Even over 50MPH it was right around 8500.

The SP3 isn't peaky at all. It has a peak, like any setup, but it doesn't feel peaky. It should only feel peaky when couple with a narrow power band cylinder setup. This cylinder will work over a good range, and so will the SP3. The ZX is a real tuned pipe, although some say it's not because it has sound deadening in the convergent cone. A pipe tuned to work at a certain RPM is bound to be inefficient when out of it's tuned range. Even the ZX doesn't feel peaky really. The MRP and 190mechs race pipes, those feel peaky to me. Even then, they have a pretty good powerband, but it's just dead and then they hit and pull hard. They feel amazing when they hit, but they can be hard to tune for. I do like the SP3 even on this setup. I mean, it's hard to argue with a pipe that's more quiet than stock, yet has a better tone, and increases power across the board, even if it's not much. Plus you can pick one up for not a ton more than a new stock pipe.

Some of my disappointment from the lack of speeds could be related to the cylinder too. I haven't really tried anything else yet. We saw on the 49cc cylinder that all the pipes kinda sucked stock, once the cylinder was ported they all did pretty well. I have the GP on now. I need to play with it more, but it's seeming to me that it's preferring to be under where it's peak was with the ported 49cc or where other people have shown it's peak on dyno graphs. I'll have to work on the tune a bit more before I can really say though.

[90GTVert]

After more test runs, the GP also likes to stay just a little shy of it's expected RPM, right about 8,700RPM cruise. It'll still go when I put lighter weights in and get it to 9,000RPM, but it does better with less revs. I'm guessing the pipes being on the low side of their stated peaks could be the lower transfer durations. Exhaust duration is really close to the ported 49cc. I'll prob end up trying to match the ported 49cc durations in the future and see if I get anything from it.


I think the SP3 felt the best for grunt of the two, but the GP allows lighter weights to be used so it gets the revs up faster and takes off very well. The GP doesn't feel like it is weak if I get into lower revs though. MPH is just not going up a lot. Average cruise speed is increasing more than max cruise speed. It has more power to keep speed up, but it's not wanting to gain a lot. I'm starting to wonder if the 49cc torque driver could be part of that. The 90cc units extend the tracks all the way out, while the 49cc unit doesn't. A small amount a travel there could make a big difference. Could be strictly horsepower though. The faster you go, the more it takes to go faster.

[90GTVert]

Once again, power seems to peak a little under where it's expected. The ZX peaks around 9,000RPM. It'll keep going if persuaded, but best results come from sticking at 9,000 and under. It loses some low end power vs the others, but not so much that I even needed stiffer clutch springs. Power is really similar to the GP and they're pretty even on average cruise speed, but the ZX out accelerated it and should be able to get an extra MPH or two all out.

[palezu]

Nice I want to ask one thing. In the video it sounds like that when you shut the throttle, revs drop instantly to almost idle, as should to avoid motor braking. How you have accomplished that? ;D Because my scooter, when I ride full speed with WOT, and then shut the throttle, the revs don't drop, but it starts motor braking. And it does that all the way down to 10mph where the clutch disengages and then it goes to idle and I can feel the motorbrake stop and the scoot to coast freely. At least I'm using the automatic oil pump system so it doesn't harm my engine because the oil gets in no matter what the throttle position is but it's annoying

[90GTVert]

To be honest, I haven't tried to accomplish that specifically. I think it may be related to spacing the variator out. If I leave the 2 halves closer together nothing is as free. The clutch won't even work like it's supposed to.